Conventionally, a rotating electrical machine that has an annular stator core having a plurality of slots arranged in a circumferential direction, a stator winding wound around the stator core as a plurality of electrical conductors is aligned in the radial direction in the slots, and an insulating sheet member intervened between inner wall surfaces of the slots and the electrical conductors is known.
In addition, as shown in FIG. 14A to FIG. 14D of the present disclosure, for example, a single insulating sheet member 424 bent in a rectangular cylindrical shape to match a sectional shape of a slot is disclosed in Japanese Patent Application Laid-Open Publication No. 3351387.
Bend lines 424a extending in an axial direction are formed in advance by pressing an edge of a cutting tool, for example, onto the insulating sheet member 424, and the insulating sheet member 424 is folded along the bend lines 424a to form the rectangular cylindrical shape.
In this case, the bend lines 424a are formed so as to reach axial ends (i.e., ends in the axial direction) of the insulating sheet member 424.
The insulating sheet member 424 being folded in the rectangular cylindrical shape in this way is disposed so that both axial ends protrude from an end surface in the axial direction of a stator core to outside the slot.
Further, in order to prevent the insulating sheet member 424 disposed in the slot from detaching in the axial direction, as shown in FIG. 14A to FIG. 14D, a folded portion 424b folded back in the axial direction formed in the axial end of the insulating sheet member 424 is disclosed in the Publication '387.
Incidentally, in the rotary electric machine disclosed in the above Publication '387, obliquely passing sections are formed by bending in a circumferential direction electrical conductors extending outside slots from end surfaces in the axial direction of a stator core in coil end portions formed on both sides of the stator core in the axial direction.
Therefore, tears occur easily starting from the bend lines 424a by being pulled by the electrical conductor that has been folded especially in the corners in the axial ends of the insulating sheet member 424 that protrude outside the slots from the end surface in the axial direction of the stator core.
If the tears occur in this manner, the tears may progress inside the slot, or a distance between the stator winding and the stator core becomes insufficient, thus it becomes impossible to secure sufficient insulation.